From: snipped-for-privacy@gmail.com Newsgroups: rec.models.rockets,rec.answers Subject: rec.models.rockets FAQ Part 01 - General Information Followup-To: rec.models.rockets Reply-To: snipped-for-privacy@gmail.com Summary: This posting contains a list of Frequently Asked Questions (and their answers) about Model and High Power Consumer Rocketry
Archive-name: model-rockets/general Rec-models-rockets-archive-name: rockets-faq/part01 Posting-Frequency: irregular Last-modified: 2020 July 10
Rec.Models.Rockets FAQ (Frequently Asked Questions): PART 1 OF 3
GENERAL INFORMATION
1.1 What is a 'model rocket' versus a 'high power' rocket?
'Model', 'high power', 'advanced', and 'amateur' are all terms which have many definitions, depending to whom you are speaking. In r.m.r., and in the FAQ documents, the definitions (if any) accepted by the NFPA, National Association of Rocketry, and Tripoli High Power Rocketry Association are used. If these definitions conflict the NAR definition is used.
'Model rockets' are rockets that conform to the guidelines and restrictions defined in the NFPA 1122 document. In FAA regulations, model rockets are referred to as 'Class 1' rockets.
Model rockets: - weigh less than 1500 grams - contain less than 125 grams of total fuel - have no motor with more than 62.5 grams of fuel or more than 160 NS of total impulse - use only pre-manufactured, solid propellant motors - do not use metal body tubes, nose cones or fins. One inconsistency in U.S. regulations is the CPSC definition of a model rocket motor, which by their definition must have no more than 80NS total impulse.
NFPA document 1127-94 contains the most complete definition of a model and the model rocket safety code. This is the same safety code as adopted by the NAR.
'Large Model Rockets' is an old term used in the outdated FAA FAR 101 regulations. It was defined as a model rocket between 454 and 1500 grams (1 to 3.3 pounds) total liftoff weight or contains more than 113 grams but less than 125 grams of total fuel.
'High power rockets' are rockets that exceed the total weight, total propellant or single motor total impulse restrictions of model rockets. In FAA regulations, high power rockets are referred to as 'Class 2' rockets. High power rockets conform to the same guidelines for construction materials and pre-manufactured, commericially made rocket motors as model rockets. High power rockets also allow the use of metal structural components where such materials are necessary to insure structural integrity of the rocket. High power rockets have no total weight limits, but do have a single motor limit of no more than O power (40,960NS maximum total impulse) and have a total power limitation of 81,920NS total impulse.
NFPA document 1127-1985 contains the most complete definition of a high power rocket and also the high power rocketry safety code. This safety code has been adopted by both the NAR and TRA. Metal bodied rockets are allowed by NFPA 1127 where metal is required to insure structural integrity of the rocket over all of its anticipated flight.
Other common terms:
'Experimental' rockets is an ambiguous term. In the early 1980's it was used (reportedly coined by the magazine 'California Rocketry') to describe rockets that exceeded the model rocket limit at that time (1 pound total liftoff weight and no motor above F power). It has been used by the Tripoli Rocketry Association to describe the class of rockets that use pre-manufactured solid or hybrid rocket motors but that do not qualify as high power rockets. This includes metal bodied rockets and those with more than 80,000NS of total power.
'Mid-Power' rocketry is not any type of 'official' rocket designation but has been used to refer to rockets that exceed the old NFPA model rocket limit of 1 pound but still qualify as NFPA model rocket under current guidelines. These rockets typically use E through G power and are built with much the same techniques as high power rockets. The term 'Large Model Rocket' is synonymous.
'HPR-Lite' is an older designation that is not used much anymore. It is the same as 'Mid-Power.' This term originated in the 'rec.models.rockets' newsgroup.
The term 'non-professional rocketry' encompasses all forms of model, high power and amateur rocketry.
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1.2 NFPA, FAA, DOT, ... Who are all these organizations and how do they affect the rocketry hobby?
DOT (Dept. of Transportation) regulates shipping of rocket motors and reloads. CPSC (Consumer Products Safety Commission) regulates what may and not be sold as a 'consumer' items at the retail level. FAA (Federal Aviation Administration) is responsible for airspace control and regulates flights of rockets that exceed 1 pound and enter FAA regulated airspace. NFPA (National Fire Protection Association) makes recommendations for use of non-professional rocket motors. Although the NFPA only makes recommendations, most state and local laws concerning the use of model rockets are based, at least in part, on NFPA recommendations; especially NFPA 1122. The NFPA also has a draft definition and safety code for High Power rockets, NFPA 1127. BATF (Bureau of Alcohol, Tobacco and Firearms) has responsibility for regulations concerning storage and use of explosives. This agency has taken a recent interest in looking into how high power rocket motors are stored and used. ATC (Air Traffic Control) You must notify the nearest FAA ATC center prior to flying Large Model Rockets or High Power Rockets.
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1.3 What is the current legal status of model and high power rocketry in the U.S.?
A. FAA Regulations: * Class 1 Rockets (formerly model rockets and large model rockets) are defined in 14 CFR 101.22(a) of the Code of Federal Regulations. Class 1 Rockets contain less than 125 grams of total fuel, weigh less than 1500 grams (53 ounces) including propellant, are made of paper, wood, or breakable plastic, and contain no substantial metal parts. Class 1 Rockets do not require any type of FAA notification and are not restricted by the FAA. They may be launched freely except where they pose a hazard to persons, property, or other aircraft. * Class 2 Rockets (formerly high power rockets) are defined in 14 CFR 101.22(b) of the Code of Federal Regulations. Class 2 Rockets are rockets other than Class 1 Rockets that are propelled by a motor or motors having a combined total impulse of 40,960 Newton-seconds or less. Class 2 require prior authorization from the FAA before launching. * Class 2 Rockets are prohibited from flying: - into a cloud - at any altitude where the horizontal visibility is less than 5 miles - into controlled airspace - within five miles of any airport - between sunset and sunrise - within 1500-feet of any person or property that is not associated with the launch. * To obtain prior authorization, one must first apply for a Certificate of Authorization (aka waiver) using FAA Form 7711-2. B. CPSC Regulations/Restrictions: * G class model rocket motors (80.01-160.00NS total impulse) have been classified as high power by the CPSC. These motors are restricted for sale to buyers 18 years of age or older. This includes the sale of G reloadable motors. C. DOT Shipping Restrictions: * Most single use rockets motors with less than 62.5 grams of propellant are now classified as UN 1.4s and can be shipped via UPS (with a HAZMAT fee) or regular parcel post. * Most reloadable rocket motor fuel grains weighing less than 62.5 grams each are now classified as 'flammable solids' and may be shipped via UPS (with HAZMAT fee) or regular parcel post. * Any single use rocket motor containing more than 62.5 grams of fuel, and any reloadable motor fuel grain weighing more than 62.5 grams are classified as UN 1.3c, or Class B, explosives. These motors and reload grains may be shipped ONLY via Federal Express to certain designated shipping points. D. Other High Power Restrictions: * You must be 'high power certified' to purhase and fly high power rocket motors. * The NAR and Tripoli both have programs for obtaining high power certification. You need to join one or both of these organizations if you want to fly high power rockets. * You must be at least 18 years of age to become high power certified.
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1.4 What do the letters and numbers on a model rocket motor mean?
The NAR has developed a motors classification scheme which has been mandated by NFPA 1122 and most state regulations. This system specifies the motors total impulse class, average thrust, and ejection charge delay. This is printed on any motors certified by the NAR. the pieces are as follows, given the example:
E15-10W
The first letter indicates the power range, as specified in the table below. The number to the left of the dash is the average thrust of the motor, in newtons. The number to the right of the dash is the approximate ejection delay in seconds starting at the time of motor burnout. The final letter is an optional manufacturer designation for motor or fuel type. Note that letter designating total impulse of the motor specifies an impulse *range*, not an exact total impulse. For example, there are G motors that have anywhere from 90 to 160 NS of total impulse....an Aerotech G42 is rated at 90NS and a G40 is rated at
120NS. Motors with more than either 62.5 grams of total propellant or have an average thrust greater than 80 NS are considered High Power motors. You must be certified to purchase and fly these motors.
Andrew Mossberg ( snipped-for-privacy@hypertek.com) posted this chart to rmr, which includes approximate propellant weights for maximum impulse motors for each class:
C L A Low High Low High 200 ISP Propellant S Limit Limit Limit Limit Weight S (NtSec) (NtSec) (lbsSec) (lbsSec) (grams) (lbs) = ======= ======== ========= ========= ======== ======= A 1.26 2.5 0.28 0.56 1.3 0.0028 B 2.51 5.0 0.56 1.12 2.5 0.0056 C 5.01 10.0 1.13 2.25 5 0.0112 D 10.01 20.0 2.25 4.5 10 0.02 E 20.01 40.0 4.5 9 20 0.04 F 40.01 80.0 9 18 41 0.09 G 80.01 160.0 18 36 82 0.18 H 160.01 320.0 36 72 163 0.36 I 320.01 640.0 72 144 326 0.72 J 640.01 1,280.0 144 288 652 1.44 K 1280.01 2,560.0 288 575 1,305 2.88 L 2560.01 5,120.0 575 1,151 2,609 5.75 M 5120.01 10,240.0 1,151 2,301 5,219 11.5 N 10240.01 20,480.0 2,301 4,602 10,438 23.0 O 20480.01 40,960.0 4,602 9,204 20,875 46.0 P 40960.01 81,920.0 9,204 18,409 41,751 92.0
Currently, consumer rocketry stops at rockets with a total of no more than 81,920NS of total impulse. Anything larger than that is by definition an amateur rocket.
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1.5 What is a CATO? Is it CATO pronounced KAY-TO or CAT-O?
The following definition has been posted to r.m.r. by Jack Hagerty, ( snipped-for-privacy@rml.com) editor of the excellent r.m.r Glossary. For even more complete information on the term CATO, refer to the glossary.
A motor failure, generally explosive, where all the propellant is burned in a much shorter time than planned. This can be a nozzle blow-out (loud, but basically harmless), an end-cap blow-out (where all of the pyrotechnic force blows FORWARD which usually does a pretty good job of removing any internal structure including the recovery system) or a casing rupture which has unpredictable, but usually devastating, effects. Another form of CATO is an ejection failure caused by either the delay train failing to burn or the ejection charge not firing, but the result is the same: the model prangs.
Opinions on the meaning of the acronym range widely. Some say it's not an acronym at all, but simply a contraction of 'catastrophic' and should be pronounced 'Cat-o' (which sounds better than 'cata' over PA systems :-). Others maintain that it is an acronym but disagree on the meaning, offering a broad spectrum of 'CAtastrophic Take Off,' 'Catastrophically Aborted Take Off,' 'Catastrophe At Take Off' and the self referential 'CATO At Take Off.' The acronym crowd pronounces it 'Kay-Tow', like the Green Hornet's side kick. It has been pointed out, though, that all of the above are 'post-hoc' definitions since LCO's were using the term over range PA systems long before any formal acronym was established.
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Copyright (c) 2024 Wolfram v.Kiparski, editor. Refer to Part 00 for the full copyright notice.